HP 85027A/B/C Operation
SECTION 3
OPERATION
INTRODUCTION
This section contains information concerning operation of the HP 85027 directional
bridges.
OPERATING PRECAUTIONS
You can dramatically degrade the performance of the HP 85027 bridges through ESD
damage, excessive input or excessive mechanical shock. Therefore read and heed the
cautions below:
CAUTION
Do not subject the bridge to ESD. Work static-free.
Do not input mnore than +23dBm RF power or more than
±
10
volts DC.
Do not drop the
HP
85027 or subject it to mechanical shock.
CONNECTOR WEAR
The input port and test port connectors are part of the microcircuit bridge assembly.
They are not separately replaceable or field repairable although the entire assembly can
be replaced with a new or rebuilt assembly. An exception to the preceding sentence is
described in Section 8. information about exchange assemblies is in Section 6.
Repeated connections will cause the connectors to become worn with a consequent deg-
radation of performance. This is a subtle but
relentless
form of degradation. It is best
countered by using an adaptei-, or connector saver, on the test port whenever some loss
in directivity can be tolerated. Refer to Table 1-2 to see the minimal performance loss
incurred by using HP’s high quality
adapters and connector savers.
For measuring SMA devices from 10 MHz to 18 0Hz, HP recommends using the
HP 85027A with an APC-7 to 3.5mm adapter. For measuring SMA devices to
26.5 0Hz, HP recommends using the HP 85027B with one of the connector savers
(male/male or male/female) which are supplied with the bridge (see Figure 3-1).
Only high quality adapters achieve accurate, repeatable measurements and even they
must
be
replaced periodically for best performance. When calibrating, use the same
adapters and interconnect cables that will be used for measurements. Additional infor-
mation on the proper care and inspection of connectors, adapters and connector savers
is in Section 8.
OPERATING INSTRUCTIONS
Because the HP 85027 has been designed specifically to operate with the HP 8757A
scalar network analyzer, operating instructions have been included in Section 3 of the
analyzer’s Operating manual. Figure 3-2 of this manual illustrates
the features of the
bridges. Figure 3-2 shows a typical measurement setup with
the HP
8757A. When you
use the bridge with the HP 8757A, set the configuration switch on the bridge to the
3-1
